Piston lubricating structure



May 23, 1.933- L. J. McKoNE l PISTON LUBRICATING STRUCTURE Fil'd NOV. 15'.. 1928 2 Sheets-Sheet l May 23,1933. L. J. MCKONE 1,910,902

PISTON LUBRICATING STRUCTURE Filed Nov. 15. 1928 2 Sheets-Sheet 2 I/v VEA/Tw?.

Patented May 23,v 1933 PATENT OFFICE Lao nucleus, or immens n'nmnsora 'PISTON LUBBICATING STRUCTURE Application Med November i5, 1928. Serial lo. 319,408. f

Thislinvention relates to an internal combustion engine, and while the invention 1s applicable to anytype of internal combustion engine and in fact is applicable to all engines having a -reoipi'ocatlng piston, 1t particularly is designed for "the modern igh speed automoblle or aeroplane engine. The tendency in the designlng of such engines today 1s\to have smaller cylinders and 1 pistons andhigher speeds. With these high speeds, a serious lubricating Yproblem has arisen. It is desirable tohave a thin film of oil between the piston and the cylinder wall in order to revent scoring or scuing.

1'5 Heretofore the plston andthe cylinder wall have been lubricated by splashing of the oil from the crank case. It often happens that when the engine first starts there 1s not .suilcient oil about the piston and the cylinder is scored or scuifed before the piston becomes well oiled and the same thing frequently happenswhen the parts become heated after a long run.

It is an object of this invention to provide a piston and cylinder structure inv which the surfaces of the cylinder and pistonrare supplied with oilwunder pressure.'Y

It is a provide a cylinder and piston structure for an internal combustion enginein which the cylinder wall and piston are lubricated by forced lubrication or oil under pressure and at the same time the oil is kept from getting above the piston.

It is more specifically an object of this invention to provide a cylinder and piston structure lfor an internal combustion engine in which oil is forced tlrough the crank shaft and connecting rod to a hollow wrist pin andl from the wrist pin through openings in the piston to the piston and cylin-A der wall, the piston also, preferably being provided with means for returning the oil t0 the crank case.

These and other objects and advantages of the invention will be fully set forth in the following description made in connec, tion with" the accompanying drawings, in" which like reference c aracters refer to simf showlng a modification, and

urther object of, the invention to communicates with a circumferentlal passage 100.

ilar plarts throughout the several views, and in w ich l Fig. 1 is for themost part a vertical section through the piston and connecting rod, a portion of the cylinder wall being shown and portions of the connecting rod and crank shaft being shown inside elevation;

Fig. 2 is a horizontal section taken on i line 2-2 of Fig. 1 as indicated by the arrows; Fig. 3 is a partial view similar to Fig. 1,

Fi 4 a'partial vlew similar to Fig.y 1,` showlng a further modification; Referring to the drawings, particularly Fig. 1 and Fig. 2, a crank shaft' 10 is shown of a 4common type for an internal combus-l tion engine having the crank bearing portions lOa and 10b. The bearing portions 10b are 'ournaled in the stationary bearings 11 of t e engine and the bearing, 11 shown is provided with an oil receiving passage 11erl which will be connected by the conduit 12 to the usual oil circulating pump 13 of the engine. The crank shaft 1() has an oil passage 100 extending therethrough which communicates with a circumferential groovelOd in the crank portion 10b, oil being supplied to the groove 10d' through the passage 11a by the pump 13, which oil is thus forced into the passage 10c. A connecting rod `is shown containing the bushing 15 -ournaled on the crank shaft vportion 10a., w ich connecting rod carries the usual hub at its 4other end which receives the wrist pin 17. The connecting rod 14 is provided with a longitudinally extending passa e 14a which also extends through the bus ling 15 and roove 10c in the crankshaft ortion 10a. roove 10e is supplied with 011 through the lateral 4passage 10i in the crank shaft so that passage 14a is thus in communication with the The connecting rod 14 at its upper end comprises the ca ortion 146 secured to the rod by the headbdp and nutted bolts 16, shown in the dotted lines in Fig 1. This'clamps the connecting rod firmly to the wrist pin 17 so thatthe wrist pin is fixed relatively to the connecting rod. As is now generall customary, a hollow wrist pin is used an said wrist pin is shown as having a lateral opening 17a communicating with passa e 14a.. The ends of the wrist pin are close byv plugs 18 which may be secured in an suitable manner, such as by the thiea s shown, said plugs being illustrated as havin sockets 18a at their outer ends angular in cross section and ada ted to receive a removing implement. T e ends of wrist pin 17 are shown as journaled in bushings 19 secured in the hubs 20a of the piston 20. The wrist pin 17 has passages 17h at each end extending therethrough, the one of which at the left hand end of the pin as shown in Fi 1 communicates with an oiling groove 1 0. The opening 17 b communicates with a larger circumferential groove 17d, and bushing 19 at the right hand end has a hole 19a therethrough in line with groove 17d. The piston hub 20a at the right has a boss 20h thereon extending downwardly in which is formed a passage 20o in line with the hole 19a. The piston 20 has a thickened circumferential portion some distance above the bottom and a circumferential slot 20d is formed in the outer wall of the piston in` line with this enlargement. This slot 20d communicates with the o ening 20c through a lateral passage 20e. 'libe piston casting 20 will preferably bemade of alui minum and the same is illustrated as provided with a thin cast-iron sleeve 21 which is forced over the casting 20. The aluminum or metal at the bottom of the piston is s un over the lower end of' the sleeve 21. The ttom of passage 20c is plugged by a headed screw 22 which also passes through and secures a key 23 which projects laterally through piston 20 and sleeve 21 thus further insuring that sleeve 21 will be held properly in place. The sleeve 21 has a plurality of eir-v cuniferentially spaced holes 21a extending therethrough disposed substantially centrally of the slot 20d. The piston 20 is at its upper end provided with the usual ring grooves 20 three of these grooves being shown an the piston is provided with a downwardly and inwardly extendin beveled surface 20g immediately below t e lower groove 20f. The sleeve 21 terminates substantially at the lower part of this beveled surface 20g and is also* formed with an inwardly and downwardly extending beveled edge. The piston 20-is of reduced diameter within the up r end of sleeve 21 thus forming a circum erential chamber 20h and saidv piston is provided with a pluralityof cir- -cumferentially spaced small holes 20j cxtending radially therethrough substantially at the bottom of the chamber 20h. As shown in `Fi 1, the piston 20 has a central downwar y extending annular rib 20k at its top interior portion from which radiate a plurality of downwardly extending ribs exany tending to the piston wall. The piston 2O is provided on its interior with a plurality of vertically extending slots 20a. A portion of the cylinder wall 24 is shown and the rings at the upper end of the piston are indicated as 25.

In operation the crank shaft will be driven as usual by the explosions inthe cylinder above the 'piston and by the resulting reciprocatioii of the piston. After the motor is running, oil isl forced through the crank shaft 10 by the oil pump 13, said oil passing through passages 100 and 14a, into the wrist pin 17 which will be substantially filled with oil. This oil is forced out under pressure through the opening 17b and the same will pass through opening 19a into passage 20cand through assage 20e into the circumferential slot or c amber 20d. This oil will be under twenty-five pounds or more pressure and will be forced out through the openings 21a, thus coming into en age ment with the exterior periphery o the piston andy with the cylinder wall. The cylinder wall is thus lubricated by forced lubrication and will not have to depend on the splash lubrication from the oil in the crank case. It is undesirable to have the o il pass above' the piston and this will he prevented, by the lower ring 25, which will fit the cylinder -wa1l very tightly. As the piston reciprocates the lower edge of this ring will sweep the oil downwardly and this oil will pass through the slot between thc upper end'of the sleeve 21 and the beveled surface 20g. As the piston rises in the cylinder the oil will be moved into this opening, the oil thus passes into chamber 20h and can pass through openings 20j to the interior of the iston and be returned to the crank case. `IllVith the present structure, therefore, not. only is oil delivered under pressure to the piston and cylinder walls thus insurin the desired lubrication, but excess oi is taken care o and returned to the crank case so that there will not be an excessive amount of oil in the cylinder which might get above the pistons into the explosion chamber. With the described -construction the parts will be effectively lubricated and the lubrication will start substantially with the starting of the engine. A good fit can thus be made between the skirt of the piston and the cylinder with no danger of scoring' or scuiling the cylniaul der and any piston slap will be eliminated.

In the modification shown in Fi. 3 the parts are the same as already descri except that the connecting rod 26 carries a bush- 26.1 has alongitudinal passage 26a therecumferential groove' 28a in its outer surface communicates with the hole or through communicating with the hole 270iV in bushing 27. The wrist pin 28 has a ciraligned with the hole 27a, which groove assage 28o within the interior of pin 28. he in 28 is held stationary in the piston hu s 20w by av dowel screw 30 threaded 'in one of said hubs and having a ta red end enga ing a hole inthe pin 28. in 28 has a ho e281 extending therethrough communicating with the passage 20c in the piston 20, the piston bein exactly the same as alread described and aving the outer sleeve 21 t ereon.

In the operation of the device shown inr Fig. 3, the oil will be forced through passage 26a and the hole 27a into the groove 28a and thence through the hole 28a yinto the pin 28. lThe oil 'will then be forcedthrough assage 20c and assage 20e into the slot or c amber 20d and) out through the holes 21a. already described to the exterior piston surfaces and the surface of the cylinder wall. The oil will be moved by the lower ring 25-and will, as already described, pass into the chamber 20h at the upper part of the piston and return vto the crank case tlirou h the holes 20j.

In ig. 4 the piston is shown having the full floating type of wrist pin, This structure comprises a connecting rod 31 having the longitudinal passage 31a therein which aligns with the hole 32a in the bushing`32 in the upper art of the connecting rod. The hole 32a aligns with the circumferential groove 33a on the exterior of the wrist pin 33, which pin has a hole 33b therethrough aligned with the groove 33a. The pin 33 is closed at its ends by the plugs 33f similar to the plugs 18 already described. Pin 33 also has aair of holes 33e extending therethroughla jacent each end at its top, the one at the left hand ,end communicating with an oil groove 33d and the one at `the right communicating with a larger circumferential rove 33e, which latter groove aligns wit a hole 34a extending through a bushing 34 in the piston hub We of the p iston 20. Both piston hubs 20a are provided with ay bushing 34. Passa 34a communicates with a passa 20o in the piston already described. he other arts shown in Fig. 4 are as already descri d in'connection with Fig.'1.

In operation of the structure shown in Fig. 4, the oil will be forced through the passage 31a and hole 32a into the groove c 33a: and thence to the opening 33b into the wrist pin. The oil will pass out through thc openings 33e and same will thus be supplied to roove 33e from 'which it will pass through ole`34a and through assages 20c andl 20e to the chamber 20d'. he oil will pass from chamber 20d as already described, through holes 21a to the piston and cylinder f wall. In the structure lshown in Fi 4 the pin 33 is journal'd in both the bus intg 32 rom can be made o f aluminum or -brass as desited. With the described structure effecby the cylinder tive lubrication is secured withno objectionable surplus of oil and dry spots on the piston and cylinder wall, as well as other objectionable action on the cylinder wall are eliminated. vThe structure has been amply demonstrated in actual practice by a long test in an automobile'and found to be very successful. engine runs in a very quiet manner. As set forth in the description of the various modifications, the structure is applicable to all types of wrist pins. A simple wrist pin can be used and one which can'be quicklyi'nade in quantity roduction.

It will, o course, be understood that various changes may be made in the form, details, proplortions and arrangement of the parts, wit out departin from the scope of agplicaiits invention, w ich, generally state 9 With the present structure the' -ioc consists in a device capable of carrying prising a core forming the top of said iston and having a wrist pin bore intermediate its ends, a hollow wrist pin insertable laterally in said bore,'means closing the ends of said wrist pin, said core having a skirt portion below said wrist pin with a circumferential groove extending about its periphery,

a. passage affording communication between said groove and the interior of said wrist pin, a shell ti htly fitting said core above and below saiv wrist'y pin bore and formin with said groove` an annular chamber, said shell having a plurality of small holes therethrough in alinement with said chamber, and means for forcing oil into said wrist pin through said passage and into said chamber,

whereby it can pass through said holes to the cylinder Wall. l

2. An internal'combustion engine structure having in combination, a piston oom-v prising a central core forming the top of said piston having a wrist pin bore intermediate its ends, a hollow wrist pin in said bore, said core having rrin grooves at the upper end of said core, said core being beveled inwardly and 'downwardly to a portion of small diameter immediately below the lower one of said ring grooves, a thin shell tightly fitting said core above and lbelow sald wrist in bore and forming an annular chamber wlth said ortion of reduced diameter, the upper en of said shell having an outwardly and upwardly beveled ed e to form with said beveled portion of sai core an annular passage, said core having a plurality of holes therethrough adjacent the bottom of said chamber, whereby oil ,can pass through said passage into said chamber and to the interior of sald passage for oiling said wrist pin, means closing the ends of said wrist pin, means for forcing oil into said wrist pin, and means for delivering oil under pressure from said wrist pin to the skirt portion of said piston at the cylinder wall.

y pin, a thin shell of different metal than said 3. An internal combustion engine structure having in combination, a piston comprising a central core having a wrist pin bore intermediate its ends,sa1d core having ring grooves at its upper end, a hollow wrist pin in said bore, a shell tightlylitting said core above and below said wrist pin bore, means closing the ends of said wrist pin, means for delivering oil under pressure to the interior of said wrist pin, and means for delivering oil under pressure from said wrist pin to circumferentially spaced points about said piston and through said shell below said wrist pin bore. t

4. An internal combustion engine structure having in combination, a piston comprising a central core having wrist in'bosses therein intermediate its ends, said bosses having a bore therein, a wrist pin in said bore, means closing the ends of said Vwrist core surrounding said core and tightly tting the same above and below said wrist pin, said core having a ycircumferential groove thereabout below said wrist pin, said shell having a series of openings therethrough alining with said groove, means for delivering oil under pressure to the interior of said wrist pin, an opening through said wrist pin, a groove about said -wr1st pin alined with said opening, and a passage leading from said groove to said first mentioned groove whereby oil under pressure is deliv-` ered through said shell to the exterior of the skirt of sald piston.

m si ature.

In testimony whereof I aix LEONI. 

